Process for preparing a dialkyl acetal of a C8 to C30 aldehyde

ABSTRACT

Improved water resistant acetal sizing agents including 1,1-octadecoxyoctadecane are provided along with methods for their synthesis including methods in which C 8  to C 30  alkyl bromides are reacted with a polyol under basic conditions and those in which a C 8  to C 30  primary alcohol is reacted with an organic base in the presence of a suitable oxidizing agent under basic conditions.

This is a divisional of U.S. application Ser. No. 09/300,160, filed Apr.27, 1999 now U.S. Pat. No. 6,165,331 which claims the benefit of U.S.Provisional Patent Application Ser. No. 60/083,314, filed Apr. 28, 1998,the disclosure of which is hereby incorporated by reference.

BACKGROUND OF THE INVENTION

The present invention relates generally to sizing compounds, andparticularly to compounds used to provide water resistance in the paperand textile industries. Specifically, the invention relates to longchain acetal compounds which are useful as sizing agents and novelmethods for their production. A particularly preferred long chain,hydrocarbon-containing compound according to the invention is1,1-octadecoxyoctadecane, the distearyl acetal of stearyl aldehyde.Further, the invention provides two novel and unexpected methods forsynthesizing desired acetal compounds.

The paper industry has now largely converted to alkaline papermaking.The two main reasons for this change are the ability to use calciumcarbonate (CaCO₃) and the ability to make a stronger and more permanentsheet. A major consequence of this change is that rosin cannot be usedas the sizing agent in an alkaline system because rosin must be usedwith alum and the rosin/alum sizing system does not work at the higherpH range used to make alkane paper. (An exception to this are dispersedrosin sizes which have been used successfully at operating pH ranges ashigh as 6.5.) To make alkaline paper, the paper industry has turned tothe synthetic reactive sizes, ASA (alkenyl succinic anhydride) and AKD(alkyl ketene dimer). These sizing agents work well in an alkalineenvironment by reacting with the fiber to form a covalent bond betweenthe sizing compound and the hydroxyl groups on the fiber. The majorproblem with ASA and AKD is that they also react with water to form aninsoluble non-sizing material.

ASA is the largest volume sizing agent now used by the paper industryand is the reaction product of an isomerized alpha olefin (with a chainlength of C-16 to C-20) and maleic anhydride. The unsaturation and chainlengths of the starting olefin determine the melting point of the ASA(which is usually less than 9° C.) and it's sizing efficiency. BecauseASA is an anhydride, it reacts rapidly with the hydroxyl groups on thefiber to form an ester linkage and with water to form a non-sizinghydrolyzate. The rapid reaction of ASA with fiber makes it the most usedsizing agent where sizing is needed before the size press to controlpickup, but the rapid reaction with water and the resultant non-sizinghydrolyzate, can cause problems for the paper maker such as press rollpicking and machine deposits. ASA is not soluble in water and must beemulsified before use. Most ASA is emulsified using high shearemulsification equipment in the presence of a protective colloid such asstarch or a synthetic polymer. Cationic starch such as cationic potatostarch is most often used because of cost and the ready availability ofwet end starch in most mills.

Because hydrolyzed ASA deposits are a major cause of runnabilityproblems many limitations are imposed on its use. Thus, hydrolysis isminimized by using soft water, cooling the starch to room temperaturebefore making down the emulsion and using the emulsion as soon aspossible after it is made. If the emulsion must be stored for any lengthof time, the temperature must be kept low and the pH should be reducedto between 3 and 4. The ASA also must be added as close to the head boxas possible to avoid prolonged contact with water. Finally, good firstpass retention is critical so that ASA does not get into the white watersystem where it will hydrolyze and cause runnability problems. Toachieve good first pass retention, retention aids should be used andstrict attention must be paid to wet end chemistry. Stock pH and dryersettings are important to maximize size efficiency and minimizedeposits.

AKD (alkyl ketene dimer) is the other commonly used cellulose reactivealkaline sizing agent but is less preferred than ASA because of its slowon-machine sizing development and higher cost. AKD is much less reactivethan ASA, and can be emulsified by the manufacturer and shipped to themill as a ready to use product. The lactone ring in AKD reacts with thehydroxyl groups on cellulose to form a β-keto ester on the cellulosefibers. Because the AKD is less reactive than ASA, much of the sizingoccurs after the dryer section of the paper machine. In some cases, thismay be insufficient to control wet end pick-up. AKD reacts with water toform the β-keto acid which rapidly decarboxylates to form thenon-sizing, solid ketone. The reaction of AKD with water occurs veryslowly at room temperature, such that emulsified AKD has a shelf life ofat least a month. AKD sized sheets can also exhibit other problems suchas size reversion, excessive sheet slipperiness and fugitive sizing.Like ASA, AKD should be added as close to the head box as possible.

Thus, while sizing agents currently used in the paper industry workwell, they all exhibit some deficiencies. ASA's are very reactive,developing sizing within a few seconds to a few minutes. They are moreefficient than rosin, and can be used with alum at pH values as low as5. However, as ASA's are readily hydrolyzed, emulsions of these productsare not very stable and require in-mill emulsification equipment forpreparation. This process can be hard to control and the ASA, being veryreactive with water as well as cellulose, can hydrolyze with waterbefore it can react with the fiber leaving machine deposits. AKD's areless reactive than ASAs and have more stable emulsions, but are alsoless reactive with cellulose and may require several hours to developsizing and usually require the concurrent use of a retention aid. Sizereversion, fugitive sizing, and machine deposit problems are alsoencountered. Both AKD and ASA can make the sheet slippery, resulting inproblems for users of reprographic paper. ASA and AKD can alsocontribute to “telescoping” of the paper reel which can lead toconverting problems. Rosin is the lowest cost sizing product, but ismuch less efficient than ASA or AKD as a sizing agent on a per poundbasis. Because of this low efficiency, relatively high dosage rates arerequired, especially when calcium carbonate is used as the filler. Rosinalso does not work well at the higher pH range seen under ankalinepapermaking conditions.

Of interest to the present invention is the art relating to thesynthesis of acetals and ketals. Ordinarily the general preparativemethod for the synthesis of an acetal or ketal is the acid catalyzedaddition of two moles of alcohol to one mole of aldehyde or ketone, withthe formation of one mole of acetal or ketal and one mole of water.These reactions are only acid catalyzed and the products are formed byway of a hemiacetal or hemiketal intermediate. If the aldehyde is small,the reaction proceeds favorably. If the aldehyde is large, water must beremoved as the material reacts. The reaction in neither direction iscatalyzed by base, so most acetals and ketals are quite stable to bases,though they are easily hydrolyzed by acids (March, Advance OrganicChemistry, 4^(th) ed; John Wiley & Sons, New York, 1992, p. 889).

Thus, for simple aldehydes, the overall equilibrium constant isfavorable, and the acetal may be prepared simply by treating thealdehyde with two equivalents of alcohol and an acid catalyst. Withketones and larger aldehydes, the equilibrium constant for making theacetal or ketal is generally unfavorable. For most aldehydes, thealcohol can be used as the solvent to drive the equilibrium towardcompletion. For fatty acetals and ketals, the equilibrium constant isgenerally unfavorable and water must be removed during the reaction todrive the reaction to completion. Another method to prepare acetals andketals, particularly fatty acetals and ketals is transacetalation offatty aldehyde dimethyl acetals and fatty alcohols. (See for example,the disclosure of Mahadevan, Lipids, Vol. 5 (No. 6), pp. 563-565 (1969)which discloses a method for the synthesis of a C-14 acetal of fattyaldehydes and fatty alcohols by transacetalation between fatty aldehydedimethyl acetals and fatty alcohols.) Acetals and ketals are normallystable to basic conditions, but are easily hydrolyzed back to thealdehyde or ketone and the alcohol under acidic conditions.

There is a need in alkaline papermaking for a sizing agent that works inan alkaline environment and does not hydrolyze in the presence of water.This sizing agent should have a low melting point and should developsome sizing before the size press. This new sizing agent should developa predictable level of sizing and keep this sizing for the life of thesheet. The new product should be safe and made from readily availablematerials.

SUMMARY OF THE INVENTION

The present invention provides improved acetal sizing compositions andmethods for their production. Specifically, the invention providessizing methods and compositions comprising a dialkyl acetal of a C₈-C₃₀aldehyde and an emulsifying agent. Preferred emulsifying agents includestarches and synthetic polymers with cationic starch derivatives beingparticularly preferred starches. Preferred synthetic polymers includepolyacrylamides, polyamides, paper makers alum, and of particularusefulness, the synthetic polymers described in U.S. Pat. No. 4,657,946.Other retention aids may be added to the size emulsion to improveretention of the size in the sheet.

According to a preferred aspect of the invention, the acetal is thedialkyl acetal, 1,1-octadecoxyoctadecane. The sizing composition may beused in a variety of applications including the sizing of substratesselected from the group consisting of paper and textiles and isparticularly useful as a wet end size in paper manufacture.

The invention also provides new and improved methods for the synthesisof acetals under basic conditions. Specifically, the invention providesa first method of preparing a dialkyl acetal of a C₈ to C₃₀ aldehydecomprising the steps of: (a) reacting a carbohydrate with a base, inalcohol, to produce a caustic treated polyol; and (b) reacting a C₈ toC₃₀ alkyl bromide in the presence of the caustic treated polyol of step(a) and a suitable solvent to produce said dialkyl acetal. According toa preferred aspect of the invention the carbohydrate is preferablycellulose which can be in the form of cellulose fibers. The synthesis iscarried out under basic conditions with the amount of base in thereaction mixture being controlled by the amount of caustic used to treatthe fiber and the amount of said caustic treated fiber used in thereaction mixture. Accordingly, the base to fiber ratio can vary from1:100 to 2:1 and the alkyl halide to caustic treated fiber ratio canvary from 1:50 to 50:1. Further, according to a preferred aspect of theinvention the solvent of step (b) is dimethylsulfoxide (DMSO).

According to a second synthetic method of the invention a dialkyl acetalof a C₈ to C₃₀ aldehyde (preferably 1,1-octadecoxyoctadecane) isprepared by a method comprising the step of reacting a C₈ to C₃₀ primaryalcohol with an organic base in the presence of a suitable oxidizingagent. Preferably, the primary alcohols are C₈ to C₈ Preferred bases forthis reaction include: dimethylamine, ethylamine, diethylamine,n-propylamine, di-n-propylamine, tri-n-propylamine, isopropylamine,n-butylamine, sec-butylamine, tert-butylamine, cyclohexylamine,hexamethylenediamine, methylaniline, dimethylanline, o, m andp-anisidine, o, m and p-phenylenediamine, and o, m and p-toluidine.Diethylamine, triethylanine, n-propylamine, isopropylamine,n-butylamine, sec-butylanine and tert-butylamine are particularlypreferred and triethylamine is most preferred. Various oxidizing agentsmay be used according to the invention with the preferred oxidizingagent being selected from the group consisting of n-chlorosuccinimide,n-bromosuccinimide, sodium hypochlorite and chlorine.

The novel sizing compound of this invention, when used as a paper sizingagent provides more consistent and predictable sizing, does nothydrolyze and leave machine deposits, provides sizing independent of pHand has unlimited shelf life. Moreover, the sizing agents of theinvention provide improved waterproofing agents for paper, corrugatedboard including poultry boxes and milk carton stock, wood productsincluding plywood and particle board, inorganic substrates such as wallboard and textile products including those such as outdoor clothing andgear. Preferred fabrics which can be treated with the size so as torender them waterproof include but are not limited tocellulose-containing fabrics such as cotton and rayon. Moreover, thesizing compounds of the invention provide numerous improvements overother compounds currently available including improved durability due tobetter affinity of the compound to the fiber and greater potential formaking the fabric both waterproof and breathable.

DETAILED DESCRIPTION

The present invention provides improved sizing compounds and new methodsfor their synthesis. Specifically, the invention provides highlyefficient methods for producing long chain acetals under basicconditions without the requirement for water removal during thereaction. A particularly preferred compound for use as a size accordingto the invention is the acetal 1,1-octadecoxyoctadecane, C₅₄H₁₁₀O₂.

It is anticipated that most carbohydrates will work as the base support(caustic treated polyol) for the reaction of the alkyl halide to theacetal. Cellulose, in the form of wood fiber is the most convenientbecause it is insoluble in the solvent dimethylsulfoxide (DMSO) and ithas the additional advantage of being an excellent carrier for thesizing agent in the wet end of the paper machine. While cellulose iscurrently preferred as the caustic treated polyol for these reactions,starch, particularly corn and potato starch, may also be used. It hasbeen found, however, that while the reaction works well, the product ofthe caustic treated starch/alkyl halide reactions is a waxy materialthat is not as easy to use as the caustic treated cellulose/alkyl halidereaction product. A highly crosslinked starch, particularly if thestarch is in the granular form and insoluble in DMSO, should provide asuitable substrate as the base support for these reactions. Using starchas the caustic treated polyol is very desirable because conventionalsizing agents as well as those of the present invention, are preferablyemulsified with starch before being used as a sizing agent in the papermaking system.

The long chain acetals of the invention may be prepared by either of thetwo inventive methods described herein but may also be producedaccording to conventional methods known to the art. For example, whilethe acetal 1,1-octadecoxyoctadecane is preferably produced according toeither of the two methods described in the following examples it mayalso be produced according to the general method described in Mahadevan,Lipids, Vol. 5 (No. 6), pp. 563-565 (1969) or other conventionalmethods.

The sizing agents of this invention are particularly well suited to thesizing of paper under alkaline conditions due to their unique ability tosize the fiber without having to be covalently or ionically bonded tothe fiber. The sizing agents of this invention are especially useful tothe paper maker because they have a great affinity for carbohydrates,particularly cellulose and most especially wood fibers. The sizingagents of this invention will not hydrolyze in the presence of water orother paper making additives regardless of how long they are left in thesystem. Sizing material that is not retained on the first pass and getsinto the white water system will retain its effectiveness as a size.This is also true for paper that contains the sizing agent that isrepulped and added back into the paper making system. The sizingmaterial of the invention which is retained on paper which is recycledin the mill (referred to as “broke”) will not degrade and will retainits effectiveness as a size. While the sizing agents and compositions ofthe invention can be used in a variety of ways for paper sizing such aswith a size press apparatus they have been found to be particularlyuseful as sizing agents for wet end sizing in the manufacture of paper.

Tests done with handsheets sized with this material have shown nofugitive sizing or size reversion, both of which are common with othersizing compounds, particularly AKD. The sizing agents of this invention,however, do share one characteristic in common with some other sizingagents. Full sizing is not obtained until about 4 hours after the sheetswere made. While the degree of cure varies depending on the sample, ingeneral the sheets show an increase in sizing from about 50 to 100%.

The examples of this invention disclose the use of these sizing agentswith bleached hardwood and softwood pulps. These pulps are generallybelieved to be more difficult to size than mechanical pulp. It isexpected that they can be used effectively to size any common wood pulpincluding but not limited to mechanical pulp (stone groundwood, refinermechanical pulp, thermo-mechanical pulp), chemical-mechanical pulps(chemi-thermo-mechanical pulp, thermo-chemi-mechanical pulp andthermo-mechanical chemi pulp), semichemical pulps (neutral sulfitesemichemical, high yield sulfite and high yield kraft pulp), andchemical pulps (kraft, sulfite and soda pulp). The sizing agents of thisinvention should also work well sizing other cellulose containingmaterials including but not limited to fiber, thread and fabric madefrom cotton, rayon, cellulose acetate, flax, jute, straw and hemp.

While examples disclosed have taught the use of straight chain,saturated hydrocarbons to make the novel sizing compounds of thisinvention, it will be apparent to those skilled in the art that othernon-saturated and branched hydrocarbons will work equally as well.Specifically, compounds such as bromooctane, bromononane, bromodecane,bromoundecane, bromododecane, bromotetradecane, bromohexadecane,bromoicosane, 1-bromo-cis-4-octadecene,1-bromo-cis,cis-9,12-octadecadiene, 1-bromo-4-hexadecyloctadecane,1-bromo-4-tetradecyloctadecane, 1-bromo-4-hexadecylhexadecane and othersaturated, unsaturated and branched long chain alkylbromides could beused in place of or in a mixture with the straight chain alkyl halidesto lower the melting point and impart other specific properties to thesizing compound. In addition to bromine, other halogenated compoundscould be used in these reactions. Chlorooctane, chlorononane,chlorodecane, chloroundecane, chlorododecane, chlorotetradecane,chlorohexadecane, chlorooctadecane, chloroicosane,1-chloro-cis-4-octadecene, 1-chloro-cis,cis-9,12-octadecadien and otheralkyl chlorides being the most common but also including alkyl iodidesand alkyl fluorides. Likewise, octanol, nonanol, decanol, undecanol,dodecanol, tetradecanol, hexadecanol, icosanol, cis-9-octadecen-1-ol,cis,cis-9,12-octadecadiene-1-ol and other long chain saturated,unsaturated and branched alcohols could be used in place of the straightchain, saturated alcohols to impart or modify specific properties suchas the melting point, of the sizing compounds. These are just a fewexamples of the many compounds that could be used in these reactionsthat would be apparent to others skilled in the art.

To use the objects of this invention, particularly as paper sizingcompounds it is preferred that they be employed in combination with anemulsifier, preferably a cationic material, that also functions as aretention aid. Materials that are commonly used in the paper industry asemulsifying agents are cationic starch derivatives such as thoseproduced from corn, potato, tapioca, and wheat starches and the like.These starches can be primary, secondary, tertiary or quarternary aminestarches or other nitrogen containing starch derivatives. While starchis particularly preferred as an emulsifying agent for use in combinationwith the dialkyl acetal of C₈-C₃₀ aldehyde component in practice of theinvention, other cationic materials may also be used. Other suitableemulsifying agents include synthetic polymers such as polyacrylamides,polyamides, and of particular usefulness, the synthetic polymersdescribed in U.S. Pat. No. 4,657,946. In addition, components such aspaper makers alum may also be used. While these materials, both starchesand synthetic polymers are useful individually for the purposes of thisinvention, they may be combined one with another or with a surfactant toincrease their effectiveness.

The sizing agent of the present invention is particularly suitable foruses in applications including paper, fabrics and non-wovens and hasproperties by which it operates as a one-way valve for water.Specifically, the sizing agents can be applied to substrates includingbut not limited to diapers, feminine products, incontinence products,umbrellas, raincoats, street clothes, cottons, camping supplies,knapsacks, hats, upholstery, lawn furniture, car seats and trim, workclothes, in tanneries, hospital, surgical and biomedical lab wear forthe prevention of absorption of biological-aqueous fluids, tarps andcovers. The sizing agents of this invention are further contemplated tobe particularly useful for sizing items of clothing such as rain gearsuch that they will repel aqueous fluids and still remain breathable andcomfortable. The novel sizing agents of this invention are alsocontemplated to be useful for impaling stain rise to aqueous fluids.According to the invention, the sizes may be applied to substratesaccording to conventional methods at concentrations which can be readilydetermined by those of skill in the art.

The following Examples are intended to illustrate practice of thepreferred embodiments of the invention. Numerous additional embodimentsand improvements are apparent upon consideration of the followingExamples.

EXAMPLE 1

According to this example a first method for synthesizing long chainacetals is provided whereby the reaction of stearyl bromide(bromooctadecane) is carried out in DMSO (dimethyl sulfoxide) in thepresence of caustic treated cellulose. As a first step, the fiber iscaustic treated with KOH in ethanol. Specifically, a mixture of 91 gsoftwood and 227 g hardwood fiber was added to 50 pounds of tap waterand beaten for 50 minutes in a Valley beater (Valley Iron Works,Appleton, Wis.). The fiber slurry was vacuum filtered through a largeBuchner funnel to remove most of the water. About 100 g dry solids basis(ds basis) of the beaten fiber was then added to about 3.5 liters ofethanol (formula 3 A, denatured alcohol, EM Science, Gibbstown, N.J.).About 50 g of KOH was dissolved in 50 g of water and added to thefiber/alcohol slurry, and the entire mixture was heated, while stirring,to about 72° C. The mixture was held at 65-72° C. for about 15 minutesand allowed to cool to about 30° C. and vacuum filtered. The filter cakewas broken up and spread out to air dry overnight to evaporate most ofthe alcohol.

According to the second step for producing long chain acetals, 47 g ofthe caustic treated cellulose was added to about 1800 g DMSO in a 2liter Parr reactor (Parr Instrument Co., Moline, Ill.). To this mixturewas added 75 g of stearyl bromide. The mixture was reacted, withstirring, at 85° C. for at least 24 hours (longer reaction times do notappear to hurt the reaction, but also did not seem to help significantlyeither). At the end of the reaction, the mixture was cooled and vacuumfiltered through #42 Whatman filter paper. The filter cake was washedwith ethanol and then reslurried in about 3 liters of ethanol and mixedwell. The mixture was then vacuum filtered through #42 Whatman filterpaper. The filter cake was washed and again reslurried in 3 liters ofethanol, mixed, vacuum filtered and washed with ethanol. The filter cakewas then saved as an alcohol wet cake to prevent mold growth. Thetreated fiber at this point was composed of approximately 61% fiber and39% long chain hydrocarbon. Based on HPLC analysis of the hydrocarbonportion, approximately 80% of the long chain hydrocarbon was the acetal,1,1-octadecoxyoctadecane.

EXAMPLE 2

According to this example, the treated fiber of Example 1 was used as asizing agent for malting paper (bandsheets). Handsheets were made usingfrom 0.5 to 50% treated fiber (ds basis) based on ds pulp (from 10 to1000 pounds per ton). Specifically, the alcohol wet cake was added toabout 3 liters of warm water and mixed well. The mixture was then vacuumfiltered through #42 Whatman filter paper. This wet cake was thenemulsified in water and the emulsified material was added to the pulpslurry to make handsheets. Specifically, a sample of the reacted fiberwet cake was added to warm water and emulsified using a Cowles mixingblade and a laboratory mixer. For a 1% addition rate, 0.36 g (ds basis)treated fiber was added to about 440 ml tap water and heated to boilingfor about 2 hours. The mixture was then mixed with a 1⅝ inch Cowlesmixer at 1400 rpm for about 15 minutes. This emulsion was then added to2059 g of 1.575 consistency pulp slurry (the pulp slurry was made upusing 272 g bleached hardwood and 91 g bleached softwood pulp in 50pounds of water and refined to a Williams freeness of 80 seconds).Handsheets were made using a Noble and Wood (file Nobel and Wood MachineCo., Hoosick Falls, N.Y.) handsheet machine. One ml of a 1:100 solutionof Nalco 7607 (Nalco Chemical Company, One Nalco Center, Naperville,Ill.) in water was added as a retention aid to the deckle box of thehandsheet machine for half the sheets. Typical handsheet bone dry weightwas 3 g. Sizing was measured using a Hercules Size Tester (HerculesInc., Wilmington, Del.), at 80% reflectance using 1:1 napthol greendye/2% formic acid as the test solution. HST on handsheets made withretention aid were 245 seconds average; HST on handsheets made withoutretention aid were 204 seconds average.

EXAMPLE 3

According to this example, the second method of the invention forproducing a long chain acetal was carried out by reaction of stearylalcohol (octadecanol) in DMSO in the presence of an oxidizing agent andan organic base. The oxidizing agent was either n-chlorosuccinimide orchlorine and the base was triethylamine. Specifically, 1000 g ofn-chlorosuccinimide was dissolved in 1000 g of DMSO in a three literround bottom flask with agitation. In a separate two liter glass beaker,92 g of stearyl alcohol was emulsified in 1000 g of DMSO using an UltraTurrax T-50 (Janke and Kunkel, Germany) with an emulsifying/choppingblade at about 6000 rpm for about 2 minutes. To the emulsified mixtureof stearyl alcohol and DMSO was added 32 g of triethylamine. Theemulsion was immediately added to the n-chlorosuccinimide/DMSO mixturewith stirring. The mixture was heated with a heating mantle to 40° C.and held for 15 to 63 hours.

At the end of the reaction, about 4 liters of ethanol was added to thewarm reaction mixture and mixed well. As the alcohol was added, materialwould begin to precipitate out of solution. The precipitated materialwas recovered by vacuum filtering (#42 Whatman filter paper). The filtercake was washed thoroughly with ethanol and placed in a small beaker ona hot plate. The material was heated gently to about 140 to 180° C.under nitrogen to drive off remaining ethanol and DMSO. The material wasa white, crystalline solid with a melting point of 58-59° C. Totalrecovered material was about 33 g, for a yield of about 35%. The sampleswere analyzed by HPLC using two Altima C18 5 micron, 250×46 mm columns(Alltech Associates Inc., 2051 Waukegan Rd., Deerfield, Ill.) in seriesand an evaporative light scattering detector (ELSD) (Varex MKIII ELSD,Alltech Associates Inc., Deerfield, Ill.). Sample purity (of the1,1-octadecoxyoctadecane) was about 90% by HPLC analysis.

EXAMPLE 4

According to this example, handsheets were produced using the1,1-octadecoxyoctadecane product of Example 3 as the sizing agent. Totest the handsheets, the sizing agent was first emulsified with starchand the emulsified material was added to a pulp slurry. Specifically,the 1,1-octadecoxyoctadecane sample was melted and added to a 4% solids(ds basis) cooked cationic corn starch paste (Pencat® 600, PenfordProducts Co., Cedar Rapids, Iowa) at a 3:1 ratio of starch to size. Thehot starch/size mixture was emulsified using the Ultra Turrax T-50 withan emulsification blade set at 6000-8,000 rpm. The emulsion was added to2080 g of 1.57% consistency pulp slurry (The pulp slurry was made using272 g bleached hardwood pulp and 91 g bleached softwood pulp in 50pounds of water.) The pulp was refined to a Williams freeness of 59seconds. The sizing agent was added at a rate of 8 pounds per ton of dsfiber. Handsheets were made using a Nobel and Wood handsheet machine.One ml of a 1:100 solution of Nalco 7607 in water was added as aretention aid to the deckle box of the handsheet machine for half thesheets. Typical handsheet bone dry weight was 3 g. Sizing was measuredusing a Hercules Size Tester at 80% reflectance using 1:1 napthol greendye/2% formic acid as the test solution. HST on handsheets made withretention aid were 195 seconds average; HST on handsheets made withoutretention aid were 204 seconds average.

It is anticipated that numerous variations and modifications of theembodiments of the invention described above will occur to those ofordinary skill in the art when apprized of the teachings of the presentspecification. Accordingly, only such limitations as appear in theappended claims should be placed thereon.

What is claimed is:
 1. A method of preparing a dialkyl acetal of a C₈ toC₃₀ aldehyde comprising the steps of: (a) reacting a carbohydrate with abase, in alcohol, to produce a caustic treated polyol; and (b) reactinga C₈ to C₃₀ alkyl bromide in the presence of the caustic treated polyolof step (a) and a suitable solvent to produce said distearyl acetal. 2.The method of claim 1 wherein said acetal is 1,1-octadecoxyoctadecane.3. The method of claim 1 wherein said carbohydrate is cellulose.
 4. Themethod of claim 1 wherein the solvent of step (b) is dimethylsulfoxide(DMSO).
 5. A method of preparing a dialkyl acetal of a C₈ to C₃₀aldehyde comprising the step of reacting a C₈ to C₃₀ primary alcoholwith an organic base in the presence of a suitable oxidizing agent. 6.The method of claim 4 wherein said aldehyde and said primary alcohol areC₈ to C₂₄ aldehydes and alcohols.
 7. The method of claim 4 wherein saidacetal is 1,1-octadecxyoctadecane.
 8. The method of claim 4 therein saidorganic base is an alkyl amine.
 9. The method of claim 8 wherein saidalkyl amine is triethylamine.
 10. The method of claim 5 wherein saidoxidizing agent is selected from the group consisting ofn-chlorosuccinimide, n-bromosuccinimide, sodium hypochlorite andchlorine.